Palladium Nanoparticles Encapsulated in Hollow Titanosilicate Spheres as an Ideal Nanoreactor for One-pot Oxidation.

Abstract

One-pot reaction involving Pd-catalyzed H2 O2 production from H2 and O2 and Ti-catalyzed successive oxidation with H2 O2 in a single reaction vessel is an alluring strategy for the synthesis of targeted chemicals in terms of sustainability and economic competitiveness. In this study, a yolk-shell nanostructured catalyst, consisting of Pd nanoparticles (NPs) with core diameter ca. 4.0 nm and a porous titanosilicate shell of ca. 15 nm thickness, was fabricated by using an oil-in-water (O/W) microemulsion-based interfacial self-assembly approach. Compared with prototype titanosilicate-supported Pd NP catalysts and core-shell structured analogues, the yolk-shell nanostructured catalyst exhibited superior catalytic efficiency in the one-pot oxidation reaction of sulfides with 83 % H2 O2 utilization efficiency, because of the productive effect of the titanosilicate shell in limiting the diffusion of H2 O2 generated in situ over the encapsulated Pd NPs and the efficient access of the H2 O2 to the neighboring active Ti sites. This study provides promising avenues for the development of multifunctional nanostructured catalysts that are useful for one-pot reactions.